[FFmpeg-devel] [PATCH] dca: use EXT_AUDIO_ID field to determine core extensions
Kostya
kostya.shishkov
Fri Feb 18 21:03:49 CET 2011
On Fri, Feb 18, 2011 at 09:49:44PM +0200, Anssi Hannula wrote:
> This avoids the core substream extensions scan when the EXT_AUDIO_ID
> field indicates no extensions or only unsupported extensions. The scan
> is done only if the value of EXT_AUDIO_ID is unknown or indicates a
> present XCh extension which we can decode.
> ---
> libavcodec/dca.c | 69 ++++++++++++++++++++++++++++++++++++++---------------
> 1 files changed, 49 insertions(+), 20 deletions(-)
>
> diff --git a/libavcodec/dca.c b/libavcodec/dca.c
> index bdbe018..9888b56 100644
> --- a/libavcodec/dca.c
> +++ b/libavcodec/dca.c
> @@ -99,6 +99,21 @@ enum DCAExtensionMask {
> DCA_EXT_EXSS_XLL = 0x200, ///< lossless extension in ExSS
> };
>
> +/* -1 are reserved or unknown */
> +static const int dca_ext_audio_descr_mask[] = {
> + DCA_EXT_XCH,
> + -1,
> + DCA_EXT_X96,
> + DCA_EXT_XCH | DCA_EXT_X96,
> + -1,
> + -1,
> + DCA_EXT_XXCH,
> + -1,
> +};
> +
> +/* extensions that reside in core substream */
> +#define DCA_CORE_EXTS (DCA_EXT_XCH | DCA_EXT_XXCH | DCA_EXT_X96)
> +
> /* Tables for mapping dts channel configurations to libavcodec multichannel api.
> * Some compromises have been made for special configurations. Most configurations
> * are never used so complete accuracy is not needed.
> @@ -327,14 +342,12 @@ typedef struct {
> int current_subframe;
> int current_subsubframe;
>
> + int core_ext_mask; ///< present extensions in the core substream
> +
> /* XCh extension information */
> - int xch_present;
> + int xch_present; ///< XCh extension present and valid
> int xch_base_channel; ///< index of first (only) channel containing XCH data
>
> - /* Other detected extensions in the core substream */
> - int xxch_present;
> - int x96_present;
> -
> /* ExSS header parser */
> int static_fields; ///< static fields present
> int mix_metadata; ///< mixing metadata present
> @@ -1508,12 +1521,9 @@ static int dca_exss_parse_asset_header(DCAContext *s)
>
> if (!(extensions_mask & DCA_EXT_CORE))
> av_log(s->avctx, AV_LOG_WARNING, "DTS core detection mismatch.\n");
> - if (!!(extensions_mask & DCA_EXT_XCH) != s->xch_present)
> - av_log(s->avctx, AV_LOG_WARNING, "DTS XCh detection mismatch.\n");
> - if (!!(extensions_mask & DCA_EXT_XXCH) != s->xxch_present)
> - av_log(s->avctx, AV_LOG_WARNING, "DTS XXCh detection mismatch.\n");
> - if (!!(extensions_mask & DCA_EXT_X96) != s->x96_present)
> - av_log(s->avctx, AV_LOG_WARNING, "DTS X96 detection mismatch.\n");
> + if ((extensions_mask & DCA_CORE_EXTS) != s->core_ext_mask)
> + av_log(s->avctx, AV_LOG_WARNING, "DTS extensions detection mismatch (%d, %d)\n",
> + extensions_mask & DCA_CORE_EXTS, s->core_ext_mask);
>
> return 0;
> }
> @@ -1623,8 +1633,6 @@ static int dca_decode_frame(AVCodecContext * avctx,
>
>
> s->xch_present = 0;
> - s->x96_present = 0;
> - s->xxch_present = 0;
>
> s->dca_buffer_size = dca_convert_bitstream(buf, buf_size, s->dca_buffer,
> DCA_MAX_FRAME_SIZE + DCA_MAX_EXSS_HEADER_SIZE);
> @@ -1652,11 +1660,24 @@ static int dca_decode_frame(AVCodecContext * avctx,
> /* record number of core channels incase less than max channels are requested */
> num_core_channels = s->prim_channels;
>
> - /* extensions start at 32-bit boundaries into bitstream */
> - skip_bits_long(&s->gb, (-get_bits_count(&s->gb)) & 31);
> + if (s->ext_coding)
> + s->core_ext_mask = dca_ext_audio_descr_mask[s->ext_descr];
> + else
> + s->core_ext_mask = 0;
>
> core_ss_end = FFMIN(s->frame_size, s->dca_buffer_size) * 8;
>
> + /* only scan for extensions if ext_descr was unknown or indicated a
> + * supported XCh extension */
> + if (s->core_ext_mask < 0 || s->core_ext_mask & DCA_EXT_XCH) {
> +
> + /* if ext_descr was unknown, clear s->core_ext_mask so that the
> + * extensions scan can fill it up */
> + s->core_ext_mask = FFMAX(s->core_ext_mask, 0);
> +
> + /* extensions start at 32-bit boundaries into bitstream */
> + skip_bits_long(&s->gb, (-get_bits_count(&s->gb)) & 31);
> +
> while(core_ss_end - get_bits_count(&s->gb) >= 32) {
> uint32_t bits = get_bits_long(&s->gb, 32);
>
> @@ -1675,7 +1696,7 @@ static int dca_decode_frame(AVCodecContext * avctx,
> /* skip length-to-end-of-frame field for the moment */
> skip_bits(&s->gb, 10);
>
> - s->profile = FFMAX(s->profile, FF_PROFILE_DTS_ES);
> + s->core_ext_mask |= DCA_EXT_XCH;
>
> /* extension amode should == 1, number of channels in extension */
> /* AFAIK XCh is not used for more channels */
> @@ -1699,8 +1720,7 @@ static int dca_decode_frame(AVCodecContext * avctx,
> /* XXCh: extended channels */
> /* usually found either in core or HD part in DTS-HD HRA streams,
> * but not in DTS-ES which contains XCh extensions instead */
> - s->xxch_present = 1;
> - s->profile = FFMAX(s->profile, FF_PROFILE_DTS_ES);
> + s->core_ext_mask |= DCA_EXT_XXCH;
> break;
>
> case 0x1d95f262: {
> @@ -1713,8 +1733,7 @@ static int dca_decode_frame(AVCodecContext * avctx,
> av_log(avctx, AV_LOG_DEBUG, "FSIZE96 = %d bytes\n", fsize96);
> av_log(avctx, AV_LOG_DEBUG, "REVNO = %d\n", get_bits(&s->gb, 4));
>
> - s->x96_present = 1;
> - s->profile = FFMAX(s->profile, FF_PROFILE_DTS_96_24);
> + s->core_ext_mask |= DCA_EXT_X96;
> break;
> }
> }
> @@ -1722,6 +1741,16 @@ static int dca_decode_frame(AVCodecContext * avctx,
> skip_bits_long(&s->gb, (-get_bits_count(&s->gb)) & 31);
> }
>
> + } else {
> + /* no supported extensions, skip the rest of the core substream */
> + skip_bits_long(&s->gb, core_ss_end - get_bits_count(&s->gb));
> + }
> +
> + if (s->core_ext_mask & DCA_EXT_X96)
> + s->profile = FF_PROFILE_DTS_96_24;
> + else if (s->core_ext_mask & (DCA_EXT_XCH | DCA_EXT_XXCH))
> + s->profile = FF_PROFILE_DTS_ES;
> +
> /* check for ExSS (HD part) */
> if (s->dca_buffer_size - s->frame_size > 32
> && get_bits_long(&s->gb, 32) == DCA_HD_MARKER)
> --
> 1.7.3
looks reasonable
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